The "traditional" ECG diagnosis of ACO, which includes ST-elevation cutoffs based upon age and sex, excludes patients with ventricular paced rhythm (VPR).3 The small field of research on the topic of ACO in VPR has extrapolated and analyzed data from patients with left bundle branch block (LBBB). That is because VPR with right ventricular pacing and LBBB both result in depolarization from right to left through myocardium (not through conducting fibers) and thus result in similar ECG findings (e.g. wide QRS, delayed onset of depolarization, and abnormal repolarization with "discordant" [in the opposite direction of the QRS] T-waves and ST-segment deviation). In the presence of known LBBB, AHA guidelines recommend using the Sgarbossa criteria to make the diagnosis of ACO.4 Sgarbossa et al. proposed requiring at least 3 points from the following criteria for the diagnosis of acute myocardial infarction in the presence of LBBB: (1) concordant ST-segment elevation of 1 mm (0.1 mV) in at least 1 lead (5 points), (2) concordant ST-segment depression of at least 1 mm in leads V1 to V3 (3 points), or (3) excessively discordant ST-segment elevation, defined as greater than or equal to 5 mm of ST-segment elevation when the QRS complex is negative (2 points). There have been only a handful of evaluations of Sgarbossa's criteria in VPR, with variable methodologies and patient populations; sensitivities in the studies ranged from 10-53% and specificities ranged from 84-99%.5,6 Neither study used angiographic endpoints, but only used biomarker definitions of AMI; one study used a very flawed biomarker definition with no adjudication. Thus, the number of occlusions is entirely unknown and probably very small.